1. Field of the Invention
The invention pertains to a method for manufacturing a metal strip by means of continuous casting and rolling, wherein a thin slab is initially cast in a casting machine and this thin slab is subsequently rolled in at least one rolling train by utilizing the primary heat of the casting process, wherein a continuous manufacture of the metal strip (continuous rolling) can be realized in a first operating mode by directly coupling the casting machine to the at least one rolling train, and wherein a discontinuous manufacture of the metal strip (batch rolling) can be realized in a second operating mode by decoupling the casting machine from the at least one rolling train. The invention furthermore pertains to a device for manufacturing a metal strip by means of continuous casting and rolling.
2. Description of the Prior Art
Continuous thin slab/thin strip casting and rolling systems of this type are known as CSP-systems. The continuous rolling out of the casting heat has been known for quite some time, but not yet prevailed in the market. The rigid connection between the continuous casting machine and the rolling train, as well as the march of temperature through the entire system, proved to be difficult to manage. The continuous rolling out of the casting heat is known from EP 0 286 862 A1 and EP 0 771 596 B1. The casting process and the rolling process are directly coupled in this case. The continuous strip is severed by means of shears shortly before the coiler.
Similar methods for the continuous manufacture of steel strips by coupling the casting machine and the rolling train to one another are disclosed in EP 0 415 987 B2 and EP 0 889 762 B1. In order to solve the temperature problems at the relatively slow transport speed, inductive heaters are provided upstream of and within the rolling train in these publications.
An alternative technology is the rolling of individual slabs and individual strips. In the discontinuous rolling of strips, the casting process and the rolling process are decoupled from one another. The casting speed is usually very slow and the rolling process is realized independently thereof with a high speed, namely in such a way that the temperature for the final forming process lies above the minimum temperature. Systems of this type are also referred to as CSP-systems and described, for example, in EP 0 266 564 B1, in which a high reduction is realized in the thin slab system.
A similar thin slab system is also disclosed in EP 0 666 122 A1, wherein strips are discontinuously rolled by utilizing inductive heating between the first finishing stands.
The advantage of discontinuous rolling can be seen in that the casting speed and the rolling speed can be adjusted independently of one another. When rolling thin strips, it is possible, e.g., to flexibly adjust higher rolling speeds, namely even if the casting machine operates with a slower speed or its speed is currently adjusted.
Both methods—namely the continuous casting and rolling on one hand and the discontinuous casting and rolling on the other hand—are difficult to combine due to the above-described circumstances.